Patent RU-2756965-C1 (RU)
Title: Method for automatic maintenance of temperature mode of installation of low temperature gas separation by adiabatic expansion, air cooling devices and/or their combination
Inventor: ARNO OLEG BORISOVICH
IPC: F17D5/00
Filed: 2020-12-09
Granted: 2021-10-07
Abstract: FIELD: gas production and preparation. 
     SUBSTANCE: invention relates to the field of production and preparation of gas and gas condensate for long-distance transport. The method includes preliminary cleaning of the extracted gas-liquid mixture from mechanical impurities, separating from it a part of the mixture of unstable gas condensate (UGC) and an aqueous solution of the inhibitor (AIS) in the separator of the first reduction stage, which, as they accumulate in the lower part of this separator, are diverted to the liquid separator (LS). The partially purified mined mixture from this separator is fed to an air cooler (AC) controlled by an AC separate automatic control system (ACS), where it is cooled due to heat exchange with the environment. At the outlet from the AC, the gas-liquid mixture is divided into two streams, which are additionally cooled in the first sections of the gas-gas and gas-condensate recuperative heat exchangers (HE). In this case, the division into streams is carried out by a regulating valve (RV) of the gas-liquid mixture flow, installed at the inlet of the gas-condensate HE. The flows of the gas-liquid mixture, after leaving the first sections of the HE, are combined and through the valve a regulator acting as a controlled reducer is fed into a low-temperature gas separator equipped with a temperature sensor. In this separator, it is finally separated into dry cold gas and a mixture of AIS with UGC, which is sent to the inlet of the second section of the gas-condensate HE and then to LS, from which the UGC is sent to the main condensate pipeline (MCP), AIS to regeneration, and the flow of the emitted gas - the weathering gas - is transported from the LS for utilization or compressed and fed into the main gas pipeline (MGP). The cold dried gas leaving the low-temperature separator is divided into two streams, one of which is fed to the inlet of the second section of the gas-gas HE, and the second - to the bypass of this section, equipped with a gas flow rate control valve through it. This RV provides automatic maintenance of the temperature in the low-temperature separator, dried gas at the inlet to the gas-condensate gas station and UGC at the inlet to the MCP, working in tandem with the RV installed at the inlet of the gas-condensate HE. The operation of these RVs is controlled by PID controllers, implemented on the basis of the automated process control system of the installation. To control the operating mode of the CPCS, a separate, third, PID controller is used, also implemented on the basis of a CPCS. To the input of the SP tasks of all three PID controllers, the CPCS supplies a single value of the signal of the temperature setpoint T in the low-temperature gas separator, which must be maintained under the current operating conditions of the installation. At the same time, the signal of the actual temperature value - T from the temperature sensor in the low-temperature separator is fed to the PV feedback input of the same PID controllers of the CPCS. Also, the CPCS sets the order of enabling and disabling these PID controllers by sending a signal to their Start/Stop input in the form of a logical "one" and a logical "zero". 
     EFFECT: invention allows the maximum use of the cold produced at the installation for automatic maintenance of the temperature regime in the low-temperature separator and optimize the power consumption of the AC installation in compliance with the technological standards and restrictions provided for by its technological regulations. 
     1 cl, 2 dwg